Winter Northern Hemisphere weather patterns remember summer Arctic sea-ice extent

The dramatic decline in Arctic summer sea‐ice cover is a compelling indicator of change in the global climate system and has been attributed to a combination of natural and anthropogenic effects. Through its role in regulating the exchange of energy between the ocean and atmosphere, ice loss is anticipated to influence atmospheric circulation and weather patterns. By combining satellite measurements of sea‐ice extent and conventional atmospheric observations, we find that varying summer ice conditions are associated with large‐scale atmospheric features during the following autumn and winter well beyond the Arctic's boundary. Mechanisms by which the atmosphere “remembers” a reduction in summer ice cover include warming and destabilization of the lower troposphere, increased cloudiness, and slackening of the poleward thickness gradient that weakens the polar jet stream. This ice‐atmosphere relationship suggests a potential long‐range outlook for weather patterns in the northern hemisphere.